Fm Section 1 - Pioneer SX-750 Service Manual

I
6.2 FM SECTION
FM Trac(ing
1. Connect measuring equipment as shown in
Fig. 15.
2. Set FM SG to lO|Vo modulation
(x7lkHz
deviation) at 4OOHz and 100dB output.
3. On SX-750 front panel, set FM switch to ON,
FM muting to OFF and VOLUME control to
minimum position.
4. Set TC6 to center of turning range.
5. T\rne FM SG and SX-Z5O to dial readings of
9OMHz.
6. Adjust T4 core for maximum indication on
Signal meter.
7. Adjust T6 core for center of scale indication on
Tuning meter.
8. Set FM SG output to 8- 10dB and adjust cores
of T1, T2, and T3 for maximum indication on
Signal meter.
9. Ttrne FM SG and SX-250 to dial readings of
106MHz.
10. Set FM SG output to 100dB and adjust TC6
for muimum
indication on Signal meter.
11. Set FM SG output to 8-10dB and adjust TC1,
TC3. TC5 and TC6 for maximum indication on
Signal meter.
12. Repeat above adjustment steps 5 - 11 and
adjust for optimum conditions.
13. Tune FM SG and SX-750 to dial readings of
90MHz.
14. Adjust T5 core for maximum indication on
Signal meter.
L5. Detune SX-750 (to noise only).
16. Adjust T6 for center of scale indication on
Tuning meter.
17. Tune FM SG and SX-750 to dial readings of
98MHz.
18. Set FM SG output to 60dB and adjust upper
core of T7 for maximum reading on AC volt-
meter.
19. Adjust lower core of T7 for minimum audio
frequency output distortion.
20. Set FM SG for 100dB output and adjust VR1
so that Signal meter indicates 5 of the scale.
AC voltmeter Distortion meter
F M . S G
FM signal generator
F i g . 1 5